9th Biology Board solved Questions: Ch-13. Why do we fall ill? Q. What is an antibiotic? Give its one example Ans: Antibiotic is a chemical substance that kill bacteria, secreted by microorganisms which can kill the pathogens Example – Penicillin Q. (i) Which disease is more harmful : Acute or Chronic disease ? Why? (ii) Why are we advised to take bland and nourishing food when we are sick? Ans: (i) Chronic disease Because chronic diseases have drastic long term effects on people’s health as compared to acute disease (ii) (a) Such food does not contain oil or fat and spices so it is digested easily (b) It provides sufficient energy for recovery after the disease (c) It provides adequate amount of nutrients required for regeneration of cells and tissues. Q. (i) How atmospheric inert nitrogen gas is converted into usable nitrogenous form for the various life forms? (ii) Draw a labelled diagram to show nitrogen cycle in nature Ans: (i) (i) By the help of free living nitrogen f...
